1. Field of the Invention
Exemplary embodiment relate to an apparatus and method for active and passive data gathering using a stochastic model in a control network, and more specifically, to a data gathering apparatus capable of synchronizing data of other apparatuses and its own buffer at a high speed and a method thereof.
2. Discussion of Related Art
A control network is a local network that is used to transmit and receive measurement and control data in order for devices such as air conditioners, sensors, production equipment, a programmable logic controller (PLC), and supervisory control and data acquisition (SCADA) to operate in accordance with the purpose in a specific space such as a building and a plant. Various communication media and communication protocols may be used in the control network. For example, a twisted pair (TP), wireless, Ethernet, and the like may be used as the communication media. For example, BACnet, KNX, Modbus, and OPC may be used as the communication protocol.
Up to now, in general, control networks are internally used to operate a building or a plant having a network installed therein. However, recently, as applications such as big data analysis or machine to machine (M2M) emerge, cases in which measurement and control data of devices is gathered using the control network and the data is provided to systems outside the building or the plant are increasing. Examples of such systems include a building energy management system (BEMS) and a building group management system.
In order to gather measurement and control data of the control network and provide the data to an external system, a data gathering apparatus that gathers data in other devices inside the control network, stores the data in its own buffer, and transmits the data to an external service is usually utilized. Such a device is also called a data gatherer. The data gatherer utilizes control network communication media and communication protocols in order to obtain measurement and control data from internal devices of the control network, and utilizes communication networks such as the Internet in order to communicate with an external system.
The data gatherer has a significant influence on entire system performance between an external system (a system outside a site operated based on measurement and control data gathered by a data gatherer) and an internal system (a system for operating its own site process) of a site (site: such as a building and a plant). However, when there is a large amount of data to be gathered, an existing data gatherer causes a high load in the internal system which resulted in a communication failure, and increases a data gathering delay time in the external system which resulted in a quality degradation of a system service.
Up to now, in order to address performance problems related to the data gathering, the control network is expanded or the data gatherer is additionally input in general, which resulted in an increase of equipment costs. In order to address such a problem, before the network is expanded, performance improvement of data gatherer itself needs to be studied in consideration of internal and external system characteristics. However, up to now, there is no such a solution.
Meanwhile, among previously disclosed Patent Documents, when Patent Documents related to devices for gathering data from a plurality of devices without being limited to the control network are reviewed, these are mainly focused on only utilizing various external variables related to active synchronization, but there is no patent considering optimization of passive synchronization. For example, Korean Patent Application No. 2005-0000879 discloses only a device information gathering system that can perform adaptive polling in network management according to a device state and a method thereof, and US Patent Application No. 2011-0264967 discloses only a method of utilizing a virtual state machine when data is gathered from a plurality of devices.